The goal of this R21 application, in response to PA-06-256 (Exploratory/Developmental Clinical Research Grants in Obesity), is to evaluate the feasibility of conducting a longitudinal, transnational study of obesity among immigrants. Although immigrants have lower rates of obesity than the native-born, these rates converge the longer immigrants reside in the U.S. This convergence suggests that weight gain is occurring faster among immigrants. Weight gain among immigrants likely results from changes in diet, physical activity and stress. However, most prior studies of weight gain among immigrants were cross-sectional, lacked an international comparison group, and did not contain pre-migration information. Thus, studies may have been confounded by secular trends arising from the globalization of "American" foods and lifestyles. This proposed pilot study examines a natural experiment, with migration itself as the "treatment." The pilot aims to: (1) demonstrate the feasibility of enrolling three cohorts of migrants;(2) collect baseline information of dietary and physical activity patterns;(3) follow three cohorts over one year, assess strategies to minimize loss-to-followup, and evaluate retention rates. The three cohorts consists of: (1) migrants, followed from the Philippines to the U.S.;(2) non-migrants, matched on age, gender and education to the migrants, and followed within the Philippines;(3) non-migrants comprised of individuals who wish to migrate, but do not yet have the necessary clearances. Three waves of data will be collected over one year, with initial measurements taken in the Philippines. This data consists of readings from accelerometers, anthropomorphic assessments, self-reported measures, and novel information from cell phones. The cell phones will be equipped with global positioning systems (GPS) technology to track participants'locations and with cameras to allow photographs of the foods participants eat and their self- measurements of weight and waist circumference. A subsample of participants will have nurse-administered assessments across all waves. In sum, the proposed pilot study provides a unique examination of how weight gain may actually occur among immigrants to the U.S. Compared to most studies that examine immigrants after arrival in the U.S., major innovations of this study include the assessment of pre-migration experiences, a comparison group of non-immigrants in the parent country, and the use of cell phone technology to validate self-reported measures. Ultimately, this research may provide insights into the nature of weight gain among immigrants and potential avenues for intervention. PUBLIC HEALTH RELEVANCE: Rising rates of obesity in the United States and worldwide are a significant public health concern because of the many health problems associated with obesity. Immigrants are among the fastest segments of the U.S. population and further, may be gaining weight at faster rates than the general population. The identification of factors that contribute to weight gain among immigrants may provide key information for the development of primary prevention programs.